Method of and apparatus for mixing foam with plastic materials



June 11, 1929. E. M; RICKARD ET AL 1,716,932

METHOD OF AND APPARATUS FOR MIXING FOAM WITH PLASTIC MATERIALS Filed Oct. 26, 1926 2 Sheets-Sheet 1 ATTORNEY June-11, 1929. E. M. RlKARn ETA'L 1,716,932

METHOD OF AND APPARATUS FOR MIXING FOAM WITH PLASTIC MATERIALS Filed Oct. 26, 1926 2 Sheets-Sheet 2 ATTORNEY Patented June 11, 1929.

UNITED STATES PATENT OFFICE.

ERIC M. RICHARD AND JOHN RICE, OF BERKELEY, CALIFORNIA, ASSIGNORS TO THE BUBBLESTONE' COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

METHOD OF AND APFARATUS FOR MIXING FOAM WITH PLASTIC MATERIALS.

Application filed October 26, 1926. Serial No. 144,393.

. The present invention relatesto a process of making concrete or other plastic material and to an apparatus for carrying out the process, the mainobject of which isto mix foam with cement slurry for the purpose of producing cellular concrete.

L Up to the present time it has been the practicetto utilize various types of machines on the market such as mortar mixers and the like, but it hasbeen found that the action of theshovels, blades or other mixing appliances caused the foam to be partly broken up, thus adding materially to the water content of the mix, because the foam bubbles to l5 a great extent consist ofwater.

I In order to overcome this disadvantage the apparatus of the present invention has been devised, the main features of which. are the smooth, metallic blades, coiled into helical form and running preferably in opposite directions. Theseblades may be revolubly mounted in containers especially designed for them; or they may be adapted to ordinary mixers, replacing the shovels or blades originally placed therein. As a consequence the mix is not beaten up as in previously'used machines and processes, but the foam is gently carried into "the slurry and made to smoothly enter at itssurface and without unnecessary agitation. 7 v

The apparatus as shown in the accompanying drawings is intended for intermittent operation, filledand emptied through the same opening which normally and during opera- 35- tionstands as shown but is turned downwards when the container is tilted for discharging. But the apparatus may also be made to operate continuously when the con tainer is rigid and the material is introduced at the top at one end anddischarged at the other end near the bottom. The apparatus 7 must however inthe latter case be made considerably lcnger.

In the accompanying drawings one embodiment of the invention has been illustrated. a

- Figure l'shows a side elevation of the'apparatus, partly in section;

Figure 2 is a right hand end elevation of Figure 1; and

Figure 3 a section along line 3-3 of Figure 1'. v

In the drawings reference numeral 10 represents a stand of any, suitable construction and having a base 11 and two uprights 12 and 13. The upper ends ,of these uprights constitute bearings for 'an operating shaft 14. Between the shaft and the left hand bearing 15 is inserted a sleeve 16 revoluble with regard to both and on the free left end of the shaft is keyed or otherwise rigidly mounted a gear Wheel 17 meshing with a pinion 18 secured on a drive shaft 19 carrying a pulley 20 and an idler 21. The drive shaft is revolubly mounted with one end in the upright 12 and with its other end in a hearing block 22 secured on the base 11.

At its right hand end the shaft 14 is surrounded by a sleeve 23 in which it can revolve freely. The sleeve is secured by a key or the 7 like in the hub 24. of a gear wheel 25. The hub 24 is mounted to revolve in the bearing 26 at the upper end of the upright 13. The gear wheel 25 mesheswith a pinion 27 carried on a stub'shaft 28 secured in the upright 13. 'A crank handle 29 is providedfor turning the pinion 27 and gear wheel ,25. The latter is normally locked by a pawl 30 hinged as at 31 inthe carrier 32 secured on top of the bearing 26. Y

The sleeves 16, and 23 are each provided with a flange 33 and 34 respectively and to which are bolted or otherwise rigidly se' cured the end walls 35 and 36 of the drum or container 37 in which the mixing of the foam and slurry takes place. The drum is substantially of cylindrical form and is open at its upper side as at 38 with an outwardly bent lip 39, Figures 2 and 3, to facilitate dis- I charging when the drum is tilted as indicated by dot'and dash lines in Figure 2. This tilting takes place when the gears 25, 27 are turned by the crank handle 29 from its full line to its dot and dash position in the same figure. 5

Within the dru1n37 are mounted four narrow helical'blades 40, 41, 42, 43, made from thin flexible material,'preferably metal and firmly secured to radial arms 44 which are bolted or in any other suitable manner fixedly attached to the shaft 14. All of the blades are made in the form of narrow bands; two'of larger diameter, 40,41, and two of smaller diameter, 42, 43. The blades are paired on each side of a'central vertical plane along line 5 3-3, Figure 1. That is to say, the large blade 40 which hasleft hand pitch surrounds the small blade 42 which has right hand pitch,

both being on the right hand side of the vertical plane; while the large blade 41 having right hand pitch surrounds the small blade 43 having left hand pitch and both being on the left hand side of the same vertical plane. As a consequence two opposing currents will be set up by the outer or larger blades from the end walls towards said central vertical plane when the shaft and blades are turned clockwise as seen in Figure 3, while simultaneously two currents from the vertical plane towards the end walls 35, 36 are created by the inner blades in the liquid or mass contained in the drum 37. i v v The apparatus is operated in the following 7 manner: The container or drum 37 is first looked in its upright position by the pawl 30 as indicated by the full lines in the drawings.

The drum is then filled to a sufficient depth through the opening 38 with concrete slurry and on top thereof is poured into the drum a foam as prepared in accordance with the copending application of John A. and Richard B. Rice Serial No. 287,475. By a belt from an electric motor or any other source of power, the pulley QO is started, causlng the shaft 14 with the helical blades to revolve actuated by the gears 17, 18. By the smooth blades 40, 41 the foam and slurry will then be carried first centerwards by the outer blades and then returned endwards of the drum by the inner blades 42, 43 at the same time forcing the thin films of the foam gently into the slurry without unnecessary agitation or breaking up of the bubbles. A continuous current is in this manner created in the drum,

running in the directions indicated by the arrows Y, Figure 1. In this manner a very complete mixing of the foam and slurry takes place. All the foam required for the mix does not need to be poured in from the start but it may be added little by little as the mixing proceeds.

After the blades have been revolved a certain length of time all parts of the slurry and the foam become thoroughly and homogeneously mixed, thegentle and even movement of the blades causing a maximum amount of foam to be stirred into the mixture without loss of foam such as would have taken place by ordinary violent agitation.

hen the mixing has been thus completed the blades are stopped and the pawl 30 lifted out of engagement with the teeth of the wheel 25 and finally the drum 37 tilted by turning the gears 25, 27 by means of the crank handle 29, thus emptying the drum.

The apparatus has been described in the foregoing in its simplest form but it is evident that many changes in detail and construction may be made without. deviation from the scope of the claim and the right to make such changes is accordingly reserved.

What is claimed as new is:

An apparatus for incorporating a foam with a plastic mass, comprising a container adapted to hold the foam and plastic mass and a plurality of nests of helical agitators, each nest comprising an outer and an inner blade oppositely pitched with relation to each other and to the blades in the adjacent nests, substantially as set forth.

In testimony whereof we aflix our signatures.

ERIC M. RICKARD. JOHN A. RICE. 

